title: High dose bolus heparin as initial therapy before primary angioplasty for acute myocardial infarction: results of the Heparin in Early Patency (HEAP) pilot study.
abstract: OBJECTIVE
  We sought to determine the effect of high dose intravenous bolus heparin on early coronary patency before primary angioplasty.
  
  
  BACKGROUND
  Early coronary angiography after thrombolysis for acute myocardial infarction has shown better patency when intravenous heparin is used as an adjunct. The present study explores whether heparin alone can induce reperfusion.
  
  
  METHODS
  In the Heparin in Early Patency (HEAP) pilot study, 108 patients with signs and symptoms of acute myocardial infarction < 6 h eligible for primary angioplasty received a single intravenous bolus of 300 U/kg of heparin together with aspirin (160 mg chewed) in the emergency room. The median dose of bolus heparin given was 27,000 U. Patency of the infarct-related artery (IRA) was assessed by coronary angiography at a median of 85 min after the heparin bolus.
  
  
  RESULTS
  In 55 patients (51%, 95% confidence interval 38% to 64%), Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 was observed at 90 min: TIMI flow grade 3 in 33 patients (31%); TIMI flow grade 2 in 22 (20%). Thirty-two (64%) of 50 patients with symptoms < or = 2 h had TIMI flow grade 2 or 3 versus 23 (40%) of 58 patients with symptoms > 2 h (p = 0.02). No significant bleeding was seen. Two patients (2%) died in the hospital. The patency results obtained in patients treated with the high dose bolus heparin were compared with those in 108 patients from a large primary angioplasty database, who were treated with standard therapy, including aspirin but not intravenous heparin, and were matched for clinical and angiographic characteristics with the HEAP pilot study patients. They showed an 18% patency rate (p < 0.001) of the IRA (TIMI flow grade 3 in 9%, TIMI flow grade 2 in 9%) before primary angioplasty.
  
  
  CONCLUSIONS
  Early therapy with high dose heparin is associated with full coronary reperfusion in a considerable number of patients with acute myocardial infarction, especially in those treated early (< 2 h). This simple, inexpensive, probably safe and easily antagonizable treatment may be an attractive first treatment of acute myocardial infarction both before and during the hospital stay in conjunction with primary angioplasty.
authors.affiliation: University Hospital Nijmegen, The Netherlands. f.verheugt@cardio.azn.nl
authors.forename: F W
authors.initials: FW
authors.lastname: Verheugt
authors.forename: A
authors.initials: A
authors.lastname: Liem
authors.forename: F
authors.initials: F
authors.lastname: Zijlstra
authors.forename: R C
authors.initials: RC
authors.lastname: Marsh
authors.forename: G
authors.initials: G
authors.lastname: Veen
authors.forename: J G
authors.initials: JG
authors.lastname: Bronzwaer
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use*; D001241:Aspirin / Q000008:administration & dosage / Q000627:therapeutic use; D016022:Case-Control Studies; D002423:Cause of Death; D003131:Combined Modality Therapy; D016001:Confidence Intervals; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects / Q000473:pathology; D005260:Female; D006470:Hemorrhage / Q000209:etiology; D006493:Heparin / Q000008:administration & dosage / Q000627:therapeutic use*; D006760:Hospitalization; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000628:therapy; D010865:Pilot Projects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use; D012449:Safety; D015912:Thrombolytic Therapy; D014654:Vascular Patency
chemical_list: D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D006493:Heparin; D001241:Aspirin